I was talking to a guy yesterday who drives an '05 RAM with the 4.7 and 5 speed automatic transmission. He tells me he gets about 17 mpg in the city and 21 or so on the highway. This is WAY better than I do in my '06 with same engine and tranny. He tells me he took the injectors out of a hemi and put them in his 4.7. Is this possible? What other changes would need to be done. He said it was a simple replacement. Would this account for the difference in mpg? He did also say that his power was much better, too.

 

hey are likely the same size. Without looking up part numbers thats what i would guess. They would be a direct swap but changing to an injector that provides LESS fuel while the engine is still sucking in the same amount of air is a recipe for disaster.

You want some more injectors, I got some out in the shop.

 

weed, your saying the hemi injectors will put out less fuel than the 4.7L injector. do the hemi's have two injectors per cylinder so they are smaller than the 4.7's? EDIT: I think I understand what you are saying, he maybe switched to injectors that flow less so more fuel is used so he gets better milage. I agree sounds like a bad idea in the long run.

and to the OP, doing what that guy told you seems like a great way to mess up you a/f ratio and do some serious motor damage. Unless the hemi injectors flow the perfect value to improve the tune for better milage but i doubt it.

 

The hemi uses red top injectors (at least my 08 does). Only one per cylinder and I'm sure they are either the same or larger than the 4.7L, definitely not smaller. only 1 per cylinder.

 

Sorry, I read that backwards. I thought he put 4.7 injectors in his 5.7.

 

To make sure we are all clear. He put 5.7 injectors in his 4.7. His claim is more power and better fuel mileage.

 

Well guys put 6.1 injectors in their 5.7 to combat lean AFR due to LT headers or other mods. But swapping 6.1 injectors in a 5.7 with no mods would be dumping too much fuel, causing you to be rich and a waste. I imagine the same would be true if you swapped 5.7 injectors in a 4.7 with out the mods needing the extra fuel.